/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.ql.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;

/**
 * UDFAscii.
 *
 */
@Description(name = "ascii",
    value = "_FUNC_(str) - returns the numeric value of the first character"
    + " of str",
    extended = "Returns 0 if str is empty or NULL if str is NULL\n"
    + "Example:\n"
    + "  > SELECT _FUNC_('222') FROM src LIMIT 1;"
    + "  50\n"
    + "  > SELECT _FUNC_(2) FROM src LIMIT 1;\n" + "  50")
public class UDFAscii extends UDF {
  private final IntWritable result = new IntWritable();

  public IntWritable evaluate(Text s) {
    if (s == null) {
      return null;
    }

    if (s.getLength() > 0) {
      result.set(s.getBytes()[0]);
    } else {
      result.set(0);
    }

    return result;
  }
}
